Adding-machine.



v W. E. SWALM.

ADD ING MACHINE. APPLIOATIOI FILED APBJQ, 1910.

Patented June 4, 1912.

UNITED STATES PATENT OFFICE.

WILLIAM E. SWALM, 0F LOS ANGELES, CALIFORNIA, ASSIGNOR TO BURROUGHS A1)D ING MACHINE COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

ADDING-MACHINE.

Specification of Letters Patent.

Patented June 4, 1912.

To all whom it may concern Be it known that I, \VILLIAM E. SWALM, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles and State of California, have invented certain new and useful Improvements in Adding- Machines, of which the following is a specification.

The object of the present invention is to equip an adding machine with means for subtracting an item as for example when such item has been erroneously added in.

Adding machines as commonly used are equipped with means for correcting an error in setting up an amount but it sometimes happens that such error is not detected until too late to use the ordinary form of correcting means, such as a button or key to release depressedamount keys. It is common practice to eliminate the erroneously added item by overadditi'on or the adding in of the complement of the erroneously added item but this is a tedious and bothersome procedure.

By the present invention it is made possible in the case of an item having been erroneously added, to immediately set up on the keyboard this same item and directly sub-' tract it. In the form of embodiment of the invention hereinafter to be specifically described, thiscan be accomplished by simple depression of a special key and thepulling of the operating handle while such key is held down.

In the drawings which accompany and form part of this specification Figure 1 represents in left side elevation a machine of the wellzknown Burroughs type having applied thereto means for carrying out the present invention, the parts being represented in normalcondition; Fig. 2 is a similar view of part of the mechanism illustrating a changed condition due to depression of the special or subtraction key.-

As here shown the invention is adapted to the well-known Burroughs machine, a detailed description of which throughout will hardly be necessary in view of disclosures in numerous prior patents, among which it will sufiice to mention Nos. 504,963 and 505,078, issued $eptember 12, 1893, and No. 913,860, issued March 2, 1909. While thus shown by preference adapted to this particular type of machine it is to be understood that the'invention is adaptable to other types of adding machines.

ally displaced by slide strips 214 operated by the amount keys. The racks 610 are mounted through slo-t-and-pin-and-spring connections upon the forward ends of lovers 611 which at their rear ends carry the usual series of type plates 618.

The numeral 916 designates the usual adding pinions journaled in a rocking frame 910 having above and below its pivot shaft 900 studs to co-act with the usual pitman 914. The latter is pivoted at its rear end to a rock piece 913 acted upon by a wipe pawl 821 on a vibrating arm 813. Normally the pitman engages the upper stud of the frame 910 and operates to first disengage the pinions from the racks keeping them disengaged therefrom during descent of the racks, and then to reengage the pinions with the racks so that they will be turned forward when the racks are restored by the usual frame 618. This is the common operation for addin items. the pitman' 914 is disengaged from the upper stud and engaged with the lower stud of the rocking frame 910.

The numeral 293 designates the usual total 'key and 293 the subtotal key, these ke s surmounting bell crank levers 22 7 and 22 respectively, and the latter connected to a link 216 which has a one-way engagement with the bell crank lever 227. Shifting of the pit-man by depression of either of these keys is accomplished much as usual through the medium of a link 911 which has a slotand-pin connection at its upper end with the bell crank lever 22?, but for the purposes of the present invention the manner of connecting the lower-end of that link to the pitman is modified. It will of course be understood that the eifect of shifting the pitman is to leave the pinions engaged with the racks and when either total or sub-total key is depressed the descent of racks is measured by backward turning of the pinions to zero, to which end the racks are all released from the restraint of latches 415, the latter being collectively displaced by a cross rod 204 connected by side pieces or links 226 with the bell crank 227. Of course in this operation no amount keys should be depressed For taking totals and this has been provided for in two different ways. Either depression of total or sub-' total key was caused to release any depressed amount keys or a look was employed to prevent depression of total or sub-total key while any amount key was depressed.

I have thus gone into some detail with reference to old and well-known constructions and operations because in carrying out the present invention I utilize the same characteristics that come into play in operation of the old mechanism so specified. Thus to accomplish subtraction I propose to depress or shift the pitman'the same as it is shifted for totaling purposes but while amount keys are depressed and without collectively displacing the restraining detents or latches 415, and in this way to directly subtract an item by reverse rotation of the pinions 916. It is for this reason that the connection between the lower end of the link 911 and the pitman 914 is modified as before alluded to. Instead of these parts being simply pivotally connected as heretofore the link is slotted lengthwise as shown at 911? to embrace the screw stud 914 of the pitman. Obviously this permits lowering of the pitman without lowering of the link. Then I provide another link X which has a similar connection with the pitman 914, being provided at its lower end with a longitudinal slot 0; embracing a screw stud m of the pitman. The upper end of said link X is ivotally connected to a key stem X slidmgthrough the keyboard plates 212 and 213 and surmounted by a key or button X Normally the studs 91 1 and m are at the upper ends of their respective slots in the two links and it will be obvious that depression of the total key or the key X will shift the pitman downward. Now the key X has no connection with the bail for releasing the latches 415 and its depression does notaifect those latches. Neither does said key operate to release depressed amount keys nor is it locked out by depression of amount keys. In these respects it differs in function from the total key and its depression permits backward turning of pinions 916 by the descent of racks 610 as governed by the setting of stops 270 through depression of amount keys. It will be obvious therefore that through the use of this special key X an amount set up on the keyboard can be subtracted by backward rotation of the pinions 916. While, as already pointed out, modification is necessary in the connection between the link 911 and the pitman to prevent operation of the total key when the subtraction key X is depressed, it is not so essential that'there shall be a similar mode of connection between the link X and the pitman because the pulling down of the subtraction key by operation of the total key would be inconsequential. It

is of course preferable, however, not to have this subtraction key affected by depression of the total key and so the slot-and-pin connection is adopted between the link X and the pitman. The key can be held in its normal position by friction or otherwise. With the slot-and-pin connection between the total key 911 and the pitman it becomes necessary to specially provide for restoration of the pitman to its upper or normal position and to this end a spring 911" is employed as a yielding connection between the pitman and the link. It will be obvious that such spring will yield when the subtraction key X is depressed and will operate to restore the pitman when the subtraction key is released, at the same time restoring said key. It will further beseen that when the pitman has been lowered by the total key the said spring will operate to carry the pitman up again when the total key is released. It will of course be understood that this spring 911 is inferior to the spring 280 which operates as usual to normally uphold the total key.

With the above-described equipment on the adding machine the. operator has a ready means of immediately subtracting by direct process an item which has been erroneously added. No complications arise with reference to transfer or carrying operations. If a rack has partaken of trans fer movement in. the preceding adding operation as is illustrated in Fig. 2 it must descend to that extra extent in addition to descending a distance measured by the stop set in depressing an amount key and so assuming for example that the rack appearing in Fig. 2 had, in the last adding operation by reason of a transfer movement, advanced the pinion so as to show the numeral 6 and the subtraction digit in that column or order should be 7, the pinion would nevertheless turn backward eight steps since the rack descends one step in taking up the transfer or carrying movement and seven steps as controlled by the key stop. Hence the pinion is restored to the posit-ion it held prior to the erroneous addition involving a transfer or carry which in. the example assumed would have been a position exhibiting the numeral 8. It will be noted that in such backward turning of a pinion it would pass the zero point. This is not prevented by the transfer cam 924 on the pinion encountering the foot 413* of the transfer pawl 413, which encounter does take place in the totaling operation. A transfer or carry having taken place as illustrat-ed in Fig. 2 the said pawl 413 is in its rearward position so held by the usual latch 111, and such latch is not restored, permit ting restoration of the pawl 413. until the operating handle reaches the end of its for Ward stroke. Hence the foot of the pawl is out of the path of the cam 924while the rack is descending and turning the pinion backward from a position showing 6 to a position showing 8. It will be understood in this connection that the subtraction operation is performed immediately following the erroneous adding operation and without taking a blank or spacing stroke as is done before taking a total and ordinarily com- 10 pelled in such connection. i

I claim:

1. In a machine of the character described, the combination with racks, means for reciprocating the same, "manipulative means for variously limiting excursions of said racks, pinions, and meansfor engaging the latter wit-h the racks during movement of the same in one direction and disengaging the pinions from the racks during move- 2 ment of the latter in the opposite direction;

of means for reversing at will this order of engagement and disengagement of racks and pinions during excursion of racks as limited by the aforesaid manipulative means.

2. In a machine of the character described, the combination with racks, means for reci rocating the same, manipulative means or variously limiting excursions of said racks, pinions, and means for en- 3 gaging the latter with the racks during movement of the same in one direction and disengaging the pinions from the racks during movement of the latter in the opposite direction; of a key and connections for reversing at will this order of engagement and disengagement of racks and pinions during excursions of racks as limited by the aforesaid manipulative means.

3. In a machine of the character de scribed, the combination with racks, means for reciprocating the same, manipulative ,means for variously limiting excursions of said racks, pinions, a movable support for the latter; a pitman shiftably engageable 5 with said support to vary the timing of engagement between pinions and racks, and normally operating to keep the pinions disengaged from the racks throughout movement of the latter in one direction and en- 0 gaged with the racks throughout movement thereof in the opposite direction: and means applied to said pitman for reversing at will this order of engagement and disengagement of racks and pinions during excursion of racks as limited by the aforesaid manipulative means. a,

4. In a machine of the character described, the combinati'on with racks, means for reciprocating the same, manipulative 6 means for variously limitingexcursions of said racks, pinions, a movable support for the latter; a pitman shiftably engageahle with said support to vary the timing of engagement between pinions and racks, and

normally operating, to keep the pinions disvance ofthe latter and engage the pinions with the racks for return movement thereof; and a key for shifting the pitman disengaging it from the support on one side of the latters rocking center and engaging it therewith on the other side of such center and preserving the latter engagement while the racks advance in mesh with the pinions and under control of the aforesaid manipulative means for variously limiting advance of the racks.

6. In a machine of the character described, the combination with racks, means v8O support on one side or the other of its rocking center, and normally operating to dis- Y engage the pinions from the racks for adfor reciprocating the same, manipulative means for variously limiting excursions of said racks, detents for restraining the racks individually displaceable by said manipulative means, pinions normally engaged with the racks, a rocking support for said pinions;

a pitman engageable with said support on one side or the other of its rocking center, and normally operating to disengage the pinions from the racks for advance of the latter and engage the pinions with the racks for return movement thereof; and two keys separately operable but each adapted to disengage the pitman from the pinion-support on one side of the latters rocking center and engage it on the other, one only of said keys operating to collectively displace the rack-detents.

7. In a machine of the character described, the combination with racks, means for reciprocating the same, manipulative means for variously limiting excursions of said racks. detents for restraining the racks individually displaceable by said manipulative means, pinions normally engaged with the racks, a rocking support on one side or the other of its rocking center, and normally operating to disengage the pinions from the racks for advance of the latter and engage the pinions with the racks for return move-- ment thereof; a key having a slot and pin and spring connection with the pitman and adapted to disengage the latter from the pinionsupport on one side of the latters rocking center and engage therewith on the other and also adapted to collectively (lisplace the rack detents; and a separate key for merely so shifting the pitman to cause backward rotation of pinions by advance of racks as limited by the aforesaid 1nanipu lative means.

8. In a machine of the character described, the combination With racks, means for reciprocating the same manipulative means for variously limiting excursions of said racks, detents for restraining the racks individually displaceable by said manipulative means, pinions normally engaged with the racks, a rockingsupport on one side or the other of its rocking center, and

i normally operating to disengage the pinions from the racks for advance of the latter and engage the pinions with the racks for return movement thereof; a key having a slot and pin and spring connection with. the pitman and adapted to disengage the latter from the pinion-support on one. side of the latters rocking center and engage therewith on the other and also adapted to collectively displace the rack detents; and a separate key for merely so shifting the pitman to cause backward rotation of pinions by advance of racks as limited by the aforesaid manipulative means, said separate key having a slot and pin connection with the pitman.

VILLIAM E. SVVALM. Witnesses C. H. RANDALL, COLEMAN YOUNG. 

